I've only been quilting for a few months and have been hearing about people using starch so I bought some Mary Ellen Best Press. I did a few spritzes from the bottle onto my finished blocks (I put 4 blocks close together to experiment first). They got pretty "wet" and instantly started to curl and warp a bit. I let them sit for 10 minutes to dry and yet they were still really damp. I waited a few more minutes and then used the iron to dry them the rest of the way.

The did end up with a bit more stiffness to them which is nice but it seemed weird that they got so wet and they never really dried without using the iron. I have read a lot of posts that indicate you should wait till they are dry to iron them.

I was planning on doing this process to my whole pieces of fabric (1/2 to 1 yard pieces) before starting my cutting but now I'm not sure? Do you starch entire pieces of fabric?

I don't think Mary Ellen's Best Press is starch. (Starch is normally made of corn flour, but potato flour and others can be used as starch too.)

Edit: With spray starch, you need to wait for it to dry (or at least soak into the fabric so it's not just sitting on top of the fabric) before ironing so you don't scorch the starch. With Mary Ellen's Best Press, I don't think you need to do that.

To starch yardage, I mix up a solution of Sta-Flo liquid laundry starch and water, "paint" it on with a large wall-painting brush until fabric is saturated, toss in dryer, then iron with steam. It's a pretty fast method, plus my finger doesn't get sore from spraying.

If you wait for the starch or sizing to dry, hot iron won't do anything but heat the dry starch. I get my fabric almost sopping wet with starch then press dry before cutting. My fabric isn't going to distort or ravel at all.

I always spray my blocks until they are wet, then iron them dry, thats how it works. If you are spraying dark fabric, spray on the back, it helps avoid any white residue on the front that sometimes shows on dark fabrics.